1. Field of Invention
The present invention relates to a bearing retainer of a ball bearing.
2. Description of Related Art
Conventionally, a bearing retainer 1, one part of which is shown in FIG. 4, is used with a ball bearing. The bearing retainer 1 is an annular body which has a plurality of pockets 2 disposed at a given spacing, and is an integrally molded product. The pocket 2 is a portion to receive balls 11 (see FIG. 3), and by a pair of claws 3 provided per each pocket 2 the balls 11 are prevented from being removed from the pocket, and thereby it can hold the balls rotatably.
Claws 3 have a shape to be able to cover seventy-five percent of the whole periphery of the ball in order to functionally prevent the ball from being removed. For that purpose, at the time of having the ball coupled inside the pocket 2, it is necessary to push the ball to the ends of the claws 3 by adding a force and widening the claws 3.
As mentioned above, the claws 3 are deformed resiliently at the time of ball coupling, since the bearing retainer 1 is a product molded with a resin integrally. However, damage to the ball surface is possible at the time of coupling, since the force to push and widen the claws 3 is given from the surface of the ball directly. Accordingly, it has been necessary to carry out carefully the ball-coupling work in the pocket 2, and also it has been indispensable to carefully confirm if there is any damage after completion of the work.
The present invention has been made in the light of the above problem, and the object thereof is to prevent such situations in which the balls are damaged at the time of assembling the ball in the pocket of the bearing retainer thus increasing the yield rate.
In order to solve the above problem, according to a first aspect of a bearing retainer of the present invention, a resin made bearing retainer is provided having a plurality of pockets disposed at a given spacing thereon. On each pocket a pair of claws are provided to prevent a ball from being removed. A cut out portion is provided between adjacent claws to control freedom of resilient deformation of the claw.
According to the present invention, by making the resilient deformation of the claws free, due to the cut out portion, the pushing-widening force to be added to the claw at the time of coupling the ball in the pocket of the bearing retainer in the ball bearing assembling process is optimized. For reference, the freedom of the resilient deformation of the claw is controlled by the appropriate change of the shape of the cylindrical cut out portion.
Further, according to a second aspect of a bearing retainer of the present invention, the cut out portion of the first aspect is formed cylindrically. Also, at a central portion thereof a columnar projection is provided, around of which a groove to be in communication with an inner circumference of the retainer and another groove to be in communication with a periphery of the retainer are provided.
In this invention, by changing the shape of the cylindrical cut out portion (diameter, depth etc.), the freedom of the resilient deformation of the claw can be controlled. Further, also by changing the shape (diameter, depth etc.) of the grooves to be in communication with the inner circumference and the periphery of the retainer provided on the inner circumferential surface of the cylindrical cut out portion, the freedom of the resilient deformation of the claw can be controlled.
Further, the cylindrical cut out portion is used as a grease reservoir. And due to the columnar projection provided at the center of the cylindrical cut out portion, the strength of the resistance of the grease when it flows out of the cylindrical cut out portion is controlled. Further, a necessary amount of the grease is supplied through the grooves provided on the circumferential surface of the cylindrical cut out portion to be in communication with the inner circumference and the periphery of the retainer. The necessary amount of the grease to be supplied is controlled by changing appropriately the diameter and depth of the cylindrical cut out portion and the diameter and height of the columnar projection, and the shape of the communicating grooves.
According to a third aspect of a bearing retainer of the present invention, the sectional area of the groove to be in communication between the circumferential wall of the cylindrical cut out portion and the periphery of the retainer is adapted to be greater than the sectional area of the groove in communication between the circumferential wall of the cut out portion and the inner circumferential surface of the retainer.
By this arrangement, the amount of the grease supplied from the cylindrical cut out portion to the circumferential surface of the retainer, that is, the amount of the grease supplied to an inner race of the ball bearing is intentionally controlled, and thereby a large amount of the grease supplied to the inner race side at an initial stage can be prevented.
Further, according to a fourth aspect of the bearing retainer of the present invention, a width of a sectional area of the groove in communication with the periphery of the retainer is widened as it approaches the periphery of the retainer.